It is known in the production of tablets for per oral administration, to provide pharmaceutical dosage forms prior to compressing with adjuvants which, depending upon the characteristics of these adjuvants, provide a certain degree of delayed release of the active substance or substances. The adjuvants applied previously for this purpose have not been fully satisfactory and particularly were lacking with respect to the compression characteristics thereof. Examples of adjuvants of this kind used in the compounding of tablets can be found in Lehrbuch der pharmazeutischen Technologie, R Voigt, 5. Aufl., Verlag Chemie, Weinheim (1984), p 178 ff. (Handbook for Pharmaceutical Technology). The adjuvants there described include glidants, binders, fillers, sliding agents, lubricants, disintegrating agents, bumectants, adsorption agents and the like.
It is also known in the production of enterally-dissolvable tablets to subject the tableting compositions to a granulation which can bring about particle flow properties and a bulk density of the powder mixture which is satisfactory for the tableting operation. Indeed these parameters play an important role in the problem-free production of tablets on a mass production basis. The granulation step, is, however, relatively expensive and may require polymers of diverse nature which can function as binders and can effect an aggregation of the powder particles. When one recognizes that in the literature, tablet compositions having up to 20 components are known, it will be readily understood that interactions between active substances and adjuvants (inactive substances) cannot be excluded.
The literature shows countless efforts to develop tableting adjuvants which combine a plurality of such characteristics in one compound so that the number of adjuvants incorporated into a tablet can be reduced It is also desirable to eliminate a granulation step.
Examples of adjuvants which combine a plurality of favorable characteristics include microcrystalline cellulose (Avicel and Heweten) and spray-dried lactose; they are primarily advantageous for slugging and forming tablets without pregranulation.
A hemicellulose, namely Xylan, has already been recognized as a filler and disintegrating agent for tablets. (S.M. Juslin, P. Paronen: Xylan - a possible filler and disintegrant for tablets," J. Pharm. Pharmacol. 1984, 36; 256-257).
According to this publication, hemicellulose is used to produce dosage forms from which the active ingredient is made available immediately upon administration, i.e. within several seconds or at most minutes of administration per os.
In this system, the hemicellulose is used because of its good compression characteristics and because it forms a coherent tablet framework in which the active ingredient to be released is absorbed. The addition of disintegrating agents can be avoided or reduced in this system.